Mr. Shabazz, who earned notoriety as a 12-year-old when he set a fire that killed his grandmother, Malcolm X’s widow, pulled out his phone and made some calls. Twenty minutes later, Mr. Stevens said, Mr. Shabazz told him he had a plane ticket to Los Angeles for the next day, and an appointment to see a Hollywood producer in Beverly Hills on Mr. Stevens’s behalf.

But Mr. Shabazz soon ended up in Mexico City, where he died early Thursday morning in a popular tourist area after being assaulted outside a bar, the authorities said. It was a violent end to a young and tumultuous life.